Benchmark contributions

Benchmarks measure an implemented API under a named workload; they are not performance claims by themselves. Place Rust microbenchmarks beside the crate that owns the operation and use black_box around input/output to prevent irrelevant optimization. Run them with the crate's declared bench target or cargo bench -p CRATE when the complete target is available.

Record hardware, toolchain, input size, sampling characteristics, and the command used before comparing runs. Use deterministic generated fixtures or versioned datasets. A regression threshold needs a documented baseline and noise policy, not a single local timing.

Benchmark folders for future causal, regime, uncertainty, service, or plugin features may verify an explicit unsupported boundary; they must not present synthetic timing numbers as if those runtimes existed.